With the latest changes to XEdit It seems that merged patching is no longer recommended. I would suggest that you read the instructions on Git hub for the latest version of XEdit. Then if you have any questions ask them over at the discord channel for xEdit. How ever to make life easier for them before you ask a ton of questions read back a fair ways to see if it has already been answered. I am still reading through it myself at the moment.
Even though FONV and FO3 are 10 year old games, TTW 3.2 is only 3 months old. Many of the tools like xEdit are undergoing major changes and frankly that couldn't be better news. Just think of where it could be in 10 years.